Ecosystems Ecosystems Ecology is the study of Ecosystems

Ecosystems

Ecosystems Ecology is the study of Ecosystems consist of both biological and physical factors interacting, known as biotic and abiotic factors. Examples of ecosystems – marine, alpine, desert Ecosystems are largely self-sustaining they can continue into the future largely without inputs from outside the system. Ecosystems are the most complex level of biological organisation. Biomes are broad categories of ecosystems on a world-wide scale. Biomes are classified largely on climate.

Biotic Factors A COMMUNITY is the biological part of an ecosystem, and consists of all the different populations of species living in one place at a time. A POPULATION is all the individuals of one particular species living in the same area at the same time. DIVERSITY – the richness or number of different species present. – the relative distribution (evenness) of abundance of species.

Habitat is a the type of place where and organism lives. Example – a water lily in a pond Example – you in a house Organisms can be limited to one habitat or have a range of habitats Microhabitats are smaller localised areas within a habitat. Example – your bedroom in your house Example- moss on a tree trunk in a forest

Niche The role of a species within its community The way of life of an organism Where an organism lives, feeds, what it eats, when it eats, conditions it can tolerate Where a species survives – it’s status in its habitat Different features allow species to occupy different niches

Ecological Communities Littoral Zone – Biology Camp

Open Forest – Toolangi State Forest

Mallee Ecosystem

Ecological Groups Living communities in the 3 different ecosystems mentioned previously, contain very different species. BUT - There is a common pattern to each community. Members of every community can be identified as belonging to one of the following ecological groups: producers or autotrophs consumers or heterotrophs decomposers.

Producers/Autotrophs Members of an ecological community that manufacture organic compounds (glucose=chemical energy) from simple inorganic compounds (carbon dioxide), using an abiotic energy source (sunlight). Make chemical energy available for both their own use and use by all other community members of that ecosystem. PHOTOSYNTHESIS

Examples of Producers AQUATIC TERRESTRIAL MICROSCOPIC PHYTOPLANKTON TREES MACROSCOPIC ALGAE GRASSES SEAGRASSES FLOWERING PLANTS AND PINES FRESH WATER PLANTS FERNS/MOSSES NB: CYANOBACTERIA (BLUE-GREEN ALGAE) ARE ALSO PRODUCERS

CONSUMERS/HETEROTROP HS Obtain energy by eating other organisms All animals – divided into four sub-groups: HERBIVORES – EAT PLANTS eg. Caterpillars and koalas CARNIVORES – EAT ANIMALS eg. Snakes, numbats and lions OMNIVORES – EAT PLANTS AND ANIMALS eg. Humans and crows DETRITIVORES – EAT DECOMPOSING MATTER (detritus) eg. Earthworms, dung beetles and crabs. NB: Detritivores are different to DECOMPOSERS

DECOMPOSERS Release enzymes to break down organic matter outside their bodies and then absorb some of the broken down products as their source of chemical energy. Examples of broken down matter not absorbed by decomposers are Nitrates, Phosphates and other important mineral nutrients which are taken up by producers. Eg. Various species of fungi and bacteria

Interactions Within Ecosystems Occur all the time between living things (biotic) and their physical environment (abiotic), in every ecosystem. Tolerance range for abiotic factors determines an organisms ability to survive. Interactions occur within abiotic surroundings – eg large storms can change the physical landscape and the p. H of soil and water.

Ecological Interactions between organisms (biotic) and their environment (abiotic and biotic)

Types of Interactions There are several types of interactions between species, referred to as: competition predator–prey relationships parasitism mutualism commensalism.

Interactions in a living community Interactions can involve members of the same or of different species. Competition within and between species occurs when resources are limited: Intraspecific competition: within a species Interspecific competition: between more than one species. Competition between populations in a community is reduced when there is niche separation.

Competition can be in the form of visible fighting and threats or in a non-visible form known as: ALLELOPATHY – Chemical inhibition – the release of a chemical be a plant, which prevents the germination or growth of another plant species. Pine trees are renowned for this. Pheromones – are very important chemicals used for non-competitive communication between organisms, usually to attract a mate.

Predator-Prey Relationships One species (predator) kills another (prey) Carnivorous heterotrophs have: Structural, physiological and behavioural features assisting them to obtain food. Eg. Spiders build webs, big cats have canine teeth, cooperative hunting by dolphins. They have different strategies in obtaining their prey. Eg Coral polyps capture their prey, including fish, using the stinging cells on their ‘arms’ and a lion will stalk and then pounce, surprise and chase it’s prey and use teeth and claws to kill it.

Prey are not always caught Due to structural, behavioural and biochemical features. Structural: camouflage- look like something else to disguise and mimicry – look like something that is not appetising. Behavioural: remaining still or playing dead, keeping lookout and hiding, schooling – safety in numbers. Biochemical: some animals eat plants which makes them distasteful to others. These are often brightly coloured to warn predators eg. Monarch Butterfly.

Herbivore-Plant Relationships Most herbivores are insects Plants cannot run away or hide from herbivores so how do they defend themselves? Horns, spines, stinging hairs; Various plant species also produce allelochemicals Some of these chemicals include cyanide which can kill or deform insects

Ecosystems Collaborative Task Download diagrams from the student portal. Use Bubbl. us. com to create your own ecosystem mind map – to be done in pairs. Use as many keywords as you can from the list below. Use the diagrams as a guide to include examples where possible. 1. 2. 3. • • 4. 5. Ecosystem Community Population Habitat Microhabitat Niche Autotrophs • • Heterotrophs Decomposers Detritivores Biotic and Abiotic Factors Competition Predator–prey Herbivore-plant In a Power. Point slide, insert one diagram. Using the text box function, label your diagram with as many of the keywords as possible (listed above).

Parasite-Host Relationships In Animals: an organism (the parasite) lives on or in another kind (the host) and feeds on it, typically without killing it, but: the host suffers various negative effects in this relationship and only the parasite benefits. Eg ticks and mammals It’s estimated that parasites outnumber free-living species by about four to one. EXOPARASITES – live ‘on/outside’ their host. Eg. Fleas, ticks, leeches and fungi such as Tinea. ENDOPARASITES – live ‘in’ their host. Eg. Tapeworm and roundworm

Parasitoids Are a varied group of organisms, mainly small wasps and flies, that are like parasites. (The suffix -oid means ‘like’. ) Parasitoids kill their hosts, which are usually another kind of insect. They take some time to do this, unlike a predator-prey relationship in which the death of they prey is very quick.

Parasite-Host Relationships in Plants Two kinds of parasite–host relationship can be recognised, : Holoparasitism, in which the parasite is totally dependent on the host plant for all its nutrients. Eg. Rafflesia - forms largest flower on earth Hemiparasitism, in which the parasite obtains some nutrients, such as water and minerals, from its host but makes some of its own food through photosynthesis. Eg. Mistletoe

Mutualism A prolonged association of two different species in which both partners gain some benefit. Eg. Lichens consist of algae and fungi Trapezia crab and coral polyps Nitrogen fixing bacteria and certain plants which cannot extract Nitrogen form the air.

Commensalism (= ‘at the same table’) refers to the situation in which one member gains benefit and the other member neither suffers harm nor gains apparent benefit. Eg. Clown fish and Sea Anemones

Symbiosis Interactions such as parasitism, mutualism and commensalism are sometimes grouped under the general term symbiosis (= ‘living together’) - close associations between two species that have evolved over geological time.

Summary of Symbiotic Relationships Interaction Species 1 Species 2 Parasitism parasite: benefits host: harmed Mutualism species 1: benefits species 2: benefits Commensalism species 1: benefits species 2: neither harm done nor benefit gained

Natural Succession In an ecosystem, changes to physical and chemical features can cause a community to change. Succession - The natural replacement over time of one community by another community with different dominant species. Primary succession: ecological succession occurring in an area that was not previously colonised. Eg after a larval flow creates a new plateau. Secondary succession: establishment over time of replacement communities in an area following an event that removes the original community. Eg a bushfire

Pioneer Species The first species to become established in a ‘new’ habitat. can survive under harsh conditions. adapted for dispersal and rapid reproduction. typically r-selected species.

Climax Community Succession stops when a stable community becomes established, with no further change in the dominant species. This stable community is known as the climax community. The climax community depends on the physical features in the area (aspect, altitude, temperature, rainfall and soil type) Read example page 448